MANAGUA, NICARAGUA, FEB. 3 -- In the first minutes of a predawn rebel attack this week on the farming cooperative where Lucila Flores lives, a rebel bullet hit her 6-year-old daughter and left the child lying in a ditch screaming for help.

As the firefight blazed on between the rebels, known as contras, and the cooperative's progovernment militiamen, Sandinista troops in the distance launched a mortar round that shattered one wall of her shack, Flores recounted.

Then, before the contras withdrew after the two-hour battle they forced Flores to gather her few possessions and burned them, the 32-year-old mother said today at La Mascota hospital in Managua, where her daughter Adaluz is recovering from her gunshot wound.

Before the House of Representatives turned down tonight a $36.2 million aid package for the contras, military experts here had said that the war equation had changed the past six months because of a marked improvement in the combat performance of the 9,500 contra fighters operating in Nicaragua.

But in one respect the six-year-old conflict has not changed: the fighting by both sides continues to exact a heavy toll on the lives of war-battered civilians such as Lucila Flores, according to victims and human rights observers.

The political stakes in Nicaragua are high, with Washington seeking to protect U.S. security interests, the Sandinistas trying to ensure the survival of their Marxist revolution and the region's other four nations hoping to bring a measure of stability to Central America. But the fighting is still done in the backyards of the poorest and most vulnerable Nicaraguans, many of whom say they long for peace more than the victory of either side.

In all, seven civilians were killed, including three small boys and three unarmed women, in the cross fire yesterday morning at the Santa Elisa cooperative in central Boaco province. A spokeswoman for the Boaco hospital said by telephone that four other children besides Adaluz Flores suffered bullet and shrapnel injuries. Both parents of three of the wounded children, from a family named Calero Diaz, were killed, witnesses said.

The gunfire ended by dawn and within hours Sandinista Army medics were on the scene at the remote, dusty cooperative with coffins and kits to prepare the bodies for burial, witnesses said. In a rural region plagued with wartime food and material shortages of all kinds, the one thing everyone seemed prepared for was death.

In a second incident, in the far-northern hamlet of La Vigia Sur, Sandinista regulars and contra guerrillas battled with machine guns and grenades in a Jan. 30 skirmish, two American photographers reported after filming the events. Residents said stray mortar rounds came from behind Sandinista lines, opening ugly craters in the middle of the settlement and blowing apart one family's hut.

One-year old Wilma Cruz and her 17-year-old mother, Dora Cruz, were killed, and a 9-year-old boy and an elderly grandmother were among the wounded.

The civilian casualties did not abate even though, by a consensus among several non-U.S. western military observers here, the contras have displayed more disciplined field command, higher combat morale and more skilled use of antiaircraft and other sophisticated weapons. Their new successes came during the six months since the five Central American presidents signed a peace accord last Aug. 7.

"They're fighting like they're sure they will reconquer the government," said one military diplomat. The contras' sustained pressure forced Sandinista military commanders to soften their once confident assertion that the contras had been "strategically defeated."

Crucial CIA-run air resupply flights from airfields in Honduras, financed from the previous $100 million in aid, made it possible for contra units to remain deep inside Nicaragua for months -- and afforded them continuous supplies of Redeye antiaircraft missiles, light artillery shells and communications equipment.

One foreign military specialist noted that a PRO32 radio scrambler captured last week by Sandinista troops from a contra unit is state-of-the-art equipment, so modern that not even all U.S. units have them. The contras have shot down at least 12 of the government's Soviet-made helicopter gunships, rendering large heliborne operations unfeasible for the Sandinistas.

In fighting since October in the southern Rama region and in a north-central mining region, the contras carried out complex surprise assaults that involved coordinating thousands of guerrillas.

To military experts here, those attacks indicated the contras have achieved secure communications that the Sandinistas cannot intercept, and received support from local peasants, who kept their movements secret from the government. "For the first time the two forces are in balance in some war zones," said one well-informed western military observer.

However, some human rights groups still found high numbers of civilian casualties in contra attacks.

A new report by Witness for Peace, a religious organization outspokenly opposed to contra aid, lists 97 civilians killed, 143 wounded and 135 kidnaped in 48 contra actions between Aug. 7 and Jan. 15.

The list, based on on-site inquiries by American volunteers, cites contra abductions of members of local peace commissions -- set up under the terms of the regional peace plan -- and several alleged incidents of torture and rape.

Witness for Peace does not report civilian deaths provoked by Sandinista warfare and no reliable figures are available.

But the Nicaraguan lawyer in charge of a commission set up by the State Department to monitor contra human rights said the contras' top commanders have shifted their attitudes over the past year, throwing their support behind the commission's work to improve treatment of civilians.

In a telephone interview from Washington, lawyer Marta Patricia Baltodano noted that the commission had conducted several military courts-martial in recent months of contra field commanders accused of crimes against civilians. In a September 1987 trial a contra called Pinares was sentenced to seven years in jail for his role in the 1986 killing of a Protestant pastor and three other church workers in the hamlet of San Jose de las Mulas.

Top contra military commander Enrique Bermudez, who once tried to block the commission's work, signed a Dec. 22 writ ordering Pinares to serve his sentence, Baltodano said.

"It would still be premature to speak of a generalized change of behavior, but these trials have had a real impact among the fighters," Baltodano said.